Sandbox:SITOR-A

SITOR-A is one of two modes of SITOR, which stands for Simplex Teletype Over Radio. Based on CCIR 476-4. It was formerly used to transmit maritime short messages, however the maritime industry is gradually moving away from using this mode in favor of PACTOR. AMTOR is a type of SITOR used by amateur radio operators.

SITOR-A has been seed with shifts of 170 Hz, 300 Hz, 400 Hz, and 850 Hz. SITOR-A is most commonly used with 170 Hz shift and 100 Bd.

Frequencies

One of the biggest users of SITOR-A is not a maritime service - it's the Egyptian Embassy/MFA Cairo. The current version of the 2014 Digital Digest by Mike Chace-Ortiz (Spectrum Monitor editor) has an extensive description of this network. Also see the Utility DXers Forum on Groups.io for current frequency information

Video Examples

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Empfang und Decoden eines SITOR-A Signals ("RCVB" eine ägyptische Station)

Decoding Software

Hobby Level Software

• MultiPSK
• MultiMode (for Macs)
• Sorcerer
• TrueTTY

Professional Equipment/Software

• Go2decode
• Go2Monitor
• Hoka Code 3-32P
• Hoka 300-32
• Hoka 300-32P
• Krypto500
• Wavecom W-Code
• Wavecom W-Spectra
• WinRadio Universal FSK Decoder

Additional Links

• HF Digital "Tower of Babel"
• shoc Database: SITOR-A
• WAVECOM Database: SITOR-A
• Reading and Decoding the Transmissions of MFA Cairo (PDF) via UDXF website